Moving objects use imaging systems to monitor their environment. Moving objects include aircrafts, spacecrafts, satellites, space shuttles, nano-satellites, international space station, free-flying satellites, trains, ships and others. For purposes of this disclosure, a spacecraft may include all moving objects.
A spacecraft monitors its environment using imaging systems. An imaging system typically includes imaging optics and an optical detector. The imaging optics accepts external optical inputs and presents those inputs to a detector system while maintaining a known spatial relationship among the data items in the inputs, a process known as producing an image. The detector system converts the optical image into some other form in which its information content can be processed. The detector system may include human (pilot or crew's) vision, arrays of optical-to-electrical converters, or a combination thereof. The optical detector processes the input and generates information for the navigational and threat-response systems of the vehicle. Any response (offensive or defensive) by a spacecraft depends on the visual input provided by the imaging systems
Spacecraft are vulnerable to laser attacks. Laser beams are capable of saturating optical detectors in imaging systems, causing the machine equivalent of temporary blindness. The temporary blindness suffered by conventional imaging systems may lead to spatial disorientation or loss of situational awareness by the operating system or crew in unmanned and manned vehicles, respectively, causing loss of spacecraft and crew (if present).
Furthermore, conventional imaging optics form a highly diffracted image of a source of optical attack. The diffracted image “blinds” a much larger area of the optical detector than the theoretical area occupied on the detector by the image of the vehicle carrying the attacking laser. If the attacking vehicle could be assumed to not be moving, the location of the attacking vehicle would be in the center of the “blind” region. However, because the attacking vehicle will be moving, it could be anywhere in the large “blind” region, which makes it hard to accurately locate the source or an attack and mount an effective response.
Therefore, it is desirable to have an imaging system that can provide an accurate image of the region close to the source of a laser attack.